This invention relates to the protection of underground vertical walls and foundations from the changing effects of water and more particularly to an underground drainage system and a laminated sheet for use therein which facilitates the drainage of ground water to protect underground vertical walls and foundations.
The possibility of severe ground water and moisture damage to underground walls and foundations is a particularly troublesome concern for homeowners and builders. This is especially a problem when the structure includes a basement or the like located below ground. A solution is to remove water penetrating the soil adjacent the wall or foundation. Water removal prevents seepage thereof through small cracks in the wall, and reduces the hydrostatic pressure on the wall thereby preventing the formation of additional cracks.
It is a conventional practice to remove moisture by providing a drainage pipe surrounded by gravel wherein the water percolates down through the gravel away from the foundation to a drainage pipe. The foundation also may include a waterproof layer such as a coating of tar. This practice, however, has drawbacks in that the foundation and the waterproof coating invariably develop cracks resulting in leaks. The gravel/drainage pipe system may prevent small leaks from being troublesome, but if the climate and ground are particularly wet, the foundation is highly susceptible to leakage.
In an effort to alleviate the above problem it has been proposed by Daimler et al U.S. Pat. No. 3,754,362 to provide a mat of thermoplastic fibers placed over the outer side of the foundation between the wall and the ground. Water drains downwardly through these filaments to a perforated pipe at the lower end of the mat wherein the pipe collects the water and drains it away from the wall. Another solution to the problem is to use a panel or sheet having channels formed therein such as described in Healy et al U.S. Pat. No. 3,654,765, Gergsland U.S. Pat. No. 3,888,087, Pate et al 4,309,855 and Raidt et al U.S. Pat. No. 4,574,541. These solutions, however, are limited by the materials and the way they are manufactured in that they might be susceptible to cracks and fissures caused by uncareful installation and to fatigue caused by chemical attack.
It is accordingly an object of the invention to provide an underground drainage system which facilitates the drainage of ground water to protect foundations.
It is a further object of the present invention to provide a laminated sheet and a method of producing the same which facilitates the drainage of ground water to protect foundations.
It is a more specific object of the present invention to provide a laminated sheet and a method of producing the same which is both resistant to cracks and fissures and to chemical degradation. Other objects and advantages of the invention will be particularly identified below.